The present invention relates to a testing device for testing structural parts and functions of motor vehicles, with a program switch which establishes the circuit connections associated with the stages of a test program, and which controls an indicator device for reproduction of corresponding actual measurements. Testing devices of this type are known, e.g. from U.S. Pat. No. 2,570,252 and German Offenlegungsschrift 2,458,644.
In another known device of this kind (Operating guide BMW program tester of Bayerische Motoren Werke (AG), the indicator device displays the actual measurements in analog form on an oscillograph, as well as in digital form by means of indicator instruments. To be able to determine and analyze a defect in the course of the testing program, the testing personnel need to have a high degree of attention and considerable experience; they have to know to what defects a wrong analog or digital value should be attributed.
An object of the present invention is to produce a testing device of the aforementioned type that will make a maximum of data available during the course of a test, with slight outlay in operation, so that the testing personnel need not have the high degree of attention and considerable experience formerly required.
The above-noted problems are solved according to particularly preferred embodiments of the present invention by providing that the program switch of the known device also controls a second indicator device for reproduction of the rated measurements associated with the program stages, from a storage.
At each program stage of the test program that runs either automatically or arbitrarily, the testing device delivers the appurtenant rated measurement in analog and/or digital form. Only a direct comparison of the rated and actual values is required. Therefore, even an unpracticed operator without testing experience will readily be able to recognize a defect and will be able to immediately interrupt the course of the test program, to initiate repair operations or further examination. Thus, the search for defects will be substantially shortened and made less expensive and the precision of defect analysis will be enhanced.
As compared to storage of the rated measurements e.g. on magnetic tape and display on a video instrument or by way of a computer, there is a further easing of the operation if the memory is a microfilm and the second indicator device is a microfilm reader device according to a particularly preferred embodiment of the invention. This makes possible a more rapid access to the rated measurements. Microfilms can be scanned and quickly and simply exchanged because they are easy to handle. The microfilm is preferably provided with supplementary indications that facilitate defect analysis, or that give instructions relating to repairs to be undertaken if a defect occurs.
The microfilm reader device is preferably an ordinary commercial cost-effective microfilm reader instrument. In alternative preferred embodiments the microfilm reader device is a television camera which is operably connected to a television picture screen. Thereby, from one central microfilm storage, a plurality of rated measurement indicator devices can be supplied, at various places.
According to a further embodiment of the present invention, the actual measurement is displayed for comparison with the rated measurement on a single indicator device. With such an arrangement a deviation of the actual from the given data can be recognized with particular ease and also with reduction of manufacturing outlay for the testing device.
Further, according to another feature of preferred embodiments of the present invention, the second indicator device (for the rated measurement) is made manually adjustable independently of the test program so that when a defect appears, the characteristic data for this defect can be reproduced on the second indicator device and thereby the defect can be verified immediately, to the extent that the storage contains these data.
The above and other objects, features and advantages of the present invention will become more apparent from the description of a preferred embodiment set forth hereinafter when considered in conjunction with the accompanying drawings wherein the same reference numerals are used to designate like parts throughout the several figures.